This image features all the classic findings in Rosai-Dorfman disease; large histiocytes with central nucleoli and emperipolesis, with a background of lymphocytes and plasma cells. Gastrointestinal cases of this disease are typically found incidentally. The etiology of Rosai-Dorfman disease remains unknown. A viral infection or some type of defect in immune response has been suspected, but no conclusive evidence has been found to date. There is no specific therapy for this disease. Some cases have benefited from chemotherapy. Many cases undergo spontaneous resolution, where as others may follow a protracted clinical course lasting decades.